Magnetic hard disk drives retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive includes one or more heads that can read and write information on a corresponding magnetic surface of a spinning disk. For convenience, all heads that can read are referred to as “read heads” or “heads” herein, regardless of other devices and functions the read head may also perform (e.g. writing, micro-actuation, flying height control, touch down detection, lapping control, localized disk media heating, etc). Each read head is a sub-component of a head gimbal assembly (HGA). The HGA also includes a suspension assembly for holding the head and providing a plurality of electrical connections thereto. The suspension assembly typically includes a fragile laminated flexure to carry the electrical signals to and from the head.
The head typically comprises a slider that includes an air bearing surface (ABS) that faces the magnetic disk surface, a trailing face, and a mounting face that is opposite the ABS and that faces away from the ABS. A magnetic sensor and a plurality of head bond pads are typically disposed on the trailing face of the slider. The mounting face of the slider is typically permanently bonded to a tongue portion of the fragile laminated flexure by an adhesive, in a position such that the plurality of head bond pads are aligned with corresponding bond pads on the laminated flexure.
Conventionally, the head writes tiny magnetic transitions on the magnetic disk surface by applying sufficient magnetic field to the desired microscopic disk surface location to overcome the coercivity of the disk surface material there, and thereby change the remnant field there. However, market demand for disk drives having ever higher data storage capacity has motivated investigation into the possible use of “energy assisted” magnetic recording (EAMR), in which writing is accomplished not only by local application of a magnetic field, but also by local application of laser light for localized heating of the disk surface. EAMR may enable the writing of smaller transitions, and thereby increase the areal density of data stored on the disk surface.
Most proposed EAMR technologies require the addition of a laser light source on the read head. For example, a laser diode may be attached to a laser submount, and the laser submount attached to the mounting face of the slider. Solder alloys have been used for such attachment, for example to enhance thermal and/or electrical conductivity. However, the melting temperature of such a solder alloy may be too high to be tolerated by affected components during the manufacturing process. For example, eutectic 80Au20Sn solder alloy (i.e. having 80% gold and 20% tin by weight) is known to have favorable mechanical properties, but its melting point may exceed the maximum temperature that is practically allowable in a particular manufacturing process. By contrast, 10Au90Sn solder alloy has a lower melting point, but includes the AuSn4 intermetallic that has unfavorable mechanical properties.
Accordingly, there is a need in the art for improved methods and structures to safely, reliably, and practically attach a laser light source for EAMR to a read head.